1) Here is the various stages of the tetrahedron:

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1 Andrew Yenalavitch Homework 3 CSE Winter ) ( 20 points ) Write a shader program that renders a colored tetrahedron, which gradually shrinks to a point and expands back to its original shape. While it is shrinking and expanding, the color of the tetrahedron changes. 2) ( 20 points ) Write a shader program that uses texture techniques to paste 6 different images on the 6 faces of a cube. The cube rotates and changes size from time to time. 1) Here is the various stages of the tetrahedron:

2 I started with my code from lab 8 (the color changing hexagon) and modified it so that it displays a tetrahedron, and scales in addition to changing colors. To draw the tetrahedron, I used glutsolidtetrahedron and rotated it so that the edges would be more visible: glpushmatrix(); glrotatef(30, 0,1,0); glutsolidtetrahedron(); glpopmatrix();

3 To achieve the scaling effect, I took the "r" variable I used in lab 9 to achieve the color changing effect, and plugged it into a mat4 scaling matrix. I limit "r" to be no less than 0. As the tetrahedron shrinks, its color transitions from red to blue. As the tetrahedron grows to full scale, its color transitions from blue to red. float r = 0; float b = 0; r = r * sin ( * time ); if (r < 0) r = 0; b = r; mat4 ScalarMatrix = mat4( r, 0.0, 0.0, 0.0, 0.0, r, 0.0, 0.0, 0.0, 0.0, r, 0.0, 0.0, 0.0, 0.0, 1.0 ); I also added in shader lighting effects from the brick shader example program. The light position is passed in from the application as a uniform: gluniform3f(glgetuniformlocation(programobject, "LightPosition"), 0.0, 0.0, 4.0); This position is used by the vertex shader in various lighting calculations: vec3 ecposition = vec3 (gl_modelviewmatrix * gl_vertex); vec3 tnorm = normalize(gl_normalmatrix * gl_normal); vec3 lightvec = normalize(lightposition - ecposition); vec3 reflectvec = reflect(-lightvec, tnorm); vec3 viewvec = normalize(-ecposition); float diffuse = max(dot(lightvec, tnorm), 0.0); float spec = 0.0; if (diffuse > 0.0) spec = max(dot(reflectvec, viewvec), 0.0); spec = pow(spec, 16.0); LightIntensity = DiffuseContribution * diffuse + SpecularContribution * spec; and the resulting light intensity is passed to the fragement shader with the "LightIIntensity" varrying variable. Full source code: //lab9.cpp #include <stdlib.h> #include <stdio.h> #include <string.h> #include <fcntl.h> #include <sys/types.h> #include <unistd.h>

4 #define GLEW_STATIC 1 #include <GL/glew.h> #include <GL/glu.h> #include <GL/glut.h> using namespace std; /* Global handles for the currently active program object, with its two shader objects */ GLuint programobject = 0; GLuint vertexshaderobject = 0; GLuint fragmentshaderobject = 0; static GLint win = 0; //GLfloat angle = 0; GLuint timeparam; int readshadersource(char *filename, GLchar **shader ) // Allocate memory to hold the source of our shaders. FILE *fp; int count, pos, shadersize; fp = fopen( filename, "r"); if (!fp ) return 0; pos = (int) ftell ( fp ); fseek ( fp, 0, SEEK_END ); shadersize = ( int ) ftell ( fp ) - pos; fseek ( fp, 0, SEEK_SET ); //move to end //calculates file size //rewind to beginning if ( shadersize <= 0 ) printf("shader %s empty\n", filename); return 0; shadersize += 1; *shader = (GLchar *) malloc( shadersize); // Read the source code count = (int) fread(*shader, 1, shadersize, fp); (*shader)[count] = '\0'; if (ferror(fp)) count = 0; fclose(fp); return 1; // public int installshaders(const GLchar *vertex, const GLchar *fragment) GLint vertcompiled, fragcompiled; // status values GLint linked; // Create a vertex shader object and a fragment shader object

5 vertexshaderobject = glcreateshader(gl_vertex_shader); fragmentshaderobject = glcreateshader(gl_fragment_shader); // Load source code strings into shaders, compile and link glshadersource(vertexshaderobject, 1, &vertex, NULL); glshadersource(fragmentshaderobject, 1, &fragment, NULL); glcompileshader(vertexshaderobject); glgetshaderiv(vertexshaderobject, GL_COMPILE_STATUS, &vertcompiled); glcompileshader( fragmentshaderobject ); glgetshaderiv( fragmentshaderobject, GL_COMPILE_STATUS, &fragcompiled); if (!vertcompiled!fragcompiled) return 0; // Create a program object and attach the two compiled shaders programobject = glcreateprogram(); glattachshader( programobject, vertexshaderobject); glattachshader( programobject, fragmentshaderobject); // Link the program object gllinkprogram(programobject); glgetprogramiv(programobject, GL_LINK_STATUS, &linked); if (!linked) return 0; // Install program object as part of current state gluseprogram(programobject); gluniform3f(glgetuniformlocation(programobject, "LightPosition"), 0.0, 0.0, 4.0); return 1; int init(void) const char *version; GLchar *VertexShaderSource, *FragmentShaderSource; int loadstatus = 0; version = (const char *) glgetstring(gl_version); if (version[0]!= '2' version[1]!= '.') printf("this program requires OpenGL 2.x, found %s\n", version); // exit(1); gldepthfunc(gl_less); glenable(gl_depth_test); glclearcolor(1.0f, 1.0f, 1.0f, 1.0f); readshadersource("movingv.vert", &VertexShaderSource ); readshadersource("tests.frag", &FragmentShaderSource ); loadstatus = installshaders(vertexshadersource, FragmentShaderSource); timeparam = glgetuniformlocation ( programobject, "time" ); return loadstatus;

6 static void Reshape(int width, int height) glviewport(0, 0, width, height); glmatrixmode(gl_projection); glloadidentity(); glfrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0); glmatrixmode(gl_modelview); glloadidentity(); gltranslatef(0.0f, 0.0f, -15.0f); void CleanUp(void) gldeleteshader(vertexshaderobject); gldeleteshader(fragmentshaderobject); gldeleteprogram(programobject); glutdestroywindow(win); static void Idle(void) gluniform1f( timeparam, glutget ( GLUT_ELAPSED_TIME ) ); //angle += 0.01; glutpostredisplay(); static void Key(unsigned char key, int x, int y) switch(key) case 27: CleanUp(); exit(0); break; glutpostredisplay(); void display(void) GLfloat vec[4]; glclear(gl_color_buffer_bit GL_DEPTH_BUFFER_BIT); glclearcolor( 1.0, 1.0, 1.0, 0.0 ); //get white background color glcolor3f ( 1, 0, 0 ); //red, this will have no effect if shader is loaded glpushmatrix(); glrotatef(30, 0,1,0); glutsolidtetrahedron(); glpopmatrix(); glutswapbuffers(); glflush(); int main(int argc, char *argv[]) int success = 0;

7 glutinit(&argc, argv); glutinitwindowposition( 0, 0); glutinitwindowsize(500, 500); glutinitdisplaymode(glut_rgb GLUT_DOUBLE GLUT_DEPTH); win = glutcreatewindow(argv[0]); glutreshapefunc(reshape); glutkeyboardfunc(key); glutdisplayfunc(display); glutidlefunc(idle); // Initialize the "OpenGL Extension Wrangler" library glewinit(); success = init(); if ( success ) glutmainloop(); return 0; //movingv.vert uniform float time; //value provided by application program uniform vec3 LightPosition; const float SpecularContribution = 0.3; const float DiffuseContribution = SpecularContribution; varying float LightIntensity; varying vec4 Color; void main(void) vec3 ecposition = vec3 (gl_modelviewmatrix * gl_vertex); vec3 tnorm = normalize(gl_normalmatrix * gl_normal); vec3 lightvec = normalize(lightposition - ecposition); vec3 reflectvec = reflect(-lightvec, tnorm); vec3 viewvec = normalize(-ecposition); float diffuse = max(dot(lightvec, tnorm), 0.0); float spec = 0.0; if (diffuse > 0.0) spec = max(dot(reflectvec, viewvec), 0.0); spec = pow(spec, 16.0); LightIntensity = DiffuseContribution * diffuse + SpecularContribution * spec; float r = 0; float b = 0; r = r * sin ( * time ); if (r < 0) r = 0; b = r; mat4 ScalarMatrix = mat4( r, 0.0, 0.0, 0.0, 0.0, r, 0.0, 0.0,

frag varying vec4 Color; varying float LightIntensity; void main(void) Color *=

8 0.0, 0.0, r, 0.0, 0.0, 0.0, 0.0, 1.0 ); Color = vec4(r, 0, b, 1.0); gl_position = gl_modelviewprojectionmatrix * ScalarMatrix * gl_vertex; //tests.frag varying vec4 Color; varying float LightIntensity; void main(void) Color *= LightIntensity; gl_fragcolor = Color; 2) Here is the cube rotating at full size from 2 different angles:

9 Here is the cube scaled to half size after 10 seconds: I started with the simpletex program used in lab 9 to texture the octagon and modified it to work with multiple textures. These texture names are hard-coded into the program: char faces[][20] = "front.png", "back.png", "right.png", "left.png", "top.png", "bottom.png" ; And these names are used to initialize the various texture parameters: void init2dtexture() glgentextures(6, texname); for ( int i = 0; i < 6; ++i ) GLubyte *teximage = maketeximage( faces[i] ); if (!teximage ) printf("\nerror reading %s \n", faces[i] ); exit(1); glbindtexture(gl_texture_2d, texname[i]); //now we work on texname gltexparameteri(gl_texture_2d, GL_TEXTURE_WRAP_S, GL_REPEAT); gltexparameteri(gl_texture_2d, GL_TEXTURE_WRAP_T, GL_REPEAT); gltexparameteri(gl_texture_2d, GL_TEXTURE_MAG_FILTER, GL_LINEAR); gltexparameteri(gl_texture_2d, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glteximage2d( GL_TEXTURE_2D, 0, GL_RGBA, iwidth, iheight, 0, GL_RGBA, GL_UNSIGNED_BYTE, teximage); delete teximage; Instead of an octagon, these 6 different PNG files were mapped to a cube using the technique provided by Dr. Yu from lab 9. Here is an example of one of the faces: glbegin ( GL_POLYGON ); //back face gltexcoord2f (0,0); glvertex3f (0,0,0); gltexcoord2f (1,0); glvertex3f (1,0,0);

10 gltexcoord2f (1,1); glvertex3f (1,1,0); gltexcoord2f (0,1); glvertex3f (0,1,0); glend(); Every ten seconds, the cube toggles between full size and half size. To achieve this, I used a gluttimerfunc callback function named mytimer that toggles the value of the variable "scalar" between 1.0 and 0.5. void mytimer(int id) // timer callback cout << "Timer just went off" << endl; if (scalar == 1.0) scalar = 0.5; else scalar = 1.0; glutpostredisplay(); // request redraw gluttimerfunc(10000, mytimer, 0); // reset timer for 10 seconds This value is passed to the vertex shader as a uniform and placed in the scaling matrix "ScalarMatrix". This matrix is then used to scale the shader. mat4 ScalarMatrix = mat4( scalar, 0.0, 0.0, 0.0, 0.0, scalar, 0.0, 0.0, 0.0, 0.0, scalar, 0.0, 0.0, 0.0, 0.0, 1.0 ); gl_position = gl_modelviewprojectionmatrix * RotationMatrix * ScalarMatrix * gl_vertex; In addition to the timed scaling, the cube is also rotating. To achieve this, I increment the "angle" variable in the idle function and pass this to the vertex shader as a uniform. gluniform1f( angleparam, angle ); angle += 0.01; The vertex shader finds the sine and cosine of this angle and creates 2 rotational matrices, "ZRotationMatrix" and "YRotationMatrix", which are multiplied together to form "RotationMatrix". This matrix is used to rotate the shader. float c = cos( angle ); float s = sin( angle ); mat4 ZRotationMatrix = mat4( c, -s, 0.0, 0.0, s, c, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0 ); mat4 YRotationMatrix = mat4( c, 0.0, s, 0.0, 0, 1, 0.0, 0.0, -s, 0.0, c, 0.0, 0.0, 0.0, 0.0, 1.0 ); mat4 RotationMatrix = ZRotationMatrix * YRotationMatrix;

11 gl_position = gl_modelviewprojectionmatrix * RotationMatrix * ScalarMatrix * gl_vertex; Full source code: //simpletex.cpp #include <stdlib.h> #include <stdio.h> #include <string.h> #include <fcntl.h> #include <sys/types.h> #include <unistd.h> #include <cmath> #include <iostream> #define GLEW_STATIC 1 #include <GL/glew.h> #include <GL/glu.h> #include <GL/glut.h> #include "imageio.h" using namespace std; /* Global handles for the currently active program object, with its two shader objects */ GLfloat angle = 0; GLfloat angleparam = 0; GLfloat scalar = 1.0; GLfloat scalarparam = 0; GLuint programobject = 0; GLuint vertexshaderobject = 0; GLuint fragmentshaderobject = 0; static GLint win = 0; int anglex= 0, angley = 0, anglez = 0; int objecttype = 0; static GLuint texname[6]; int iwidth = 64, iheight = 64; char faces[][20] = "front.png", "back.png", "right.png", "left.png", "top.png", "bottom.png" ; //rotation angles /* static GLubyte checkimage[iheight][iwidth][3]; void makecheckimage(void) int i, j, c; for (i = 0; i < iwidth; i++) for (j = 0; j < iheight; j++) c = ((((i&0x8)==0)^((j&0x8))==0))*255; checkimage[i][j][0] = (GLubyte) c; checkimage[i][j][1] = (GLubyte) c; checkimage[i][j][2] = (GLubyte) c;

12 */ GLubyte* maketeximage( char *loadfile ) int i, j, c, width, height; GLubyte *teximage; teximage = loadimagergba( (char *) loadfile, &width, &height); iwidth = width; iheight = height; return teximage; void init2dtexture() glgentextures(6, texname); for ( int i = 0; i < 6; ++i ) GLubyte *teximage = maketeximage( faces[i] ); if (!teximage ) printf("\nerror reading %s \n", faces[i] ); exit(1); glbindtexture(gl_texture_2d, texname[i]); //now we work on texname gltexparameteri(gl_texture_2d, GL_TEXTURE_WRAP_S, GL_REPEAT); gltexparameteri(gl_texture_2d, GL_TEXTURE_WRAP_T, GL_REPEAT); gltexparameteri(gl_texture_2d, GL_TEXTURE_MAG_FILTER, GL_LINEAR); gltexparameteri(gl_texture_2d, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glteximage2d( GL_TEXTURE_2D, 0, GL_RGBA, iwidth, iheight, 0, GL_RGBA, GL_UNSIGNED_BYTE, teximage); delete teximage; int readshadersource(char *filename, GLchar **shader ) // Allocate memory to hold the source of our shaders. FILE *fp; int count, pos, shadersize; fp = fopen( filename, "r"); if (!fp ) return 0; pos = (int) ftell ( fp ); fseek ( fp, 0, SEEK_END ); shadersize = ( int ) ftell ( fp ) - pos; fseek ( fp, 0, SEEK_SET ); //move to end //calculates file size //rewind to beginning if ( shadersize <= 0 ) printf("shader %s empty\n", filename); return 0; *shader = (GLchar *) malloc( shadersize + 1); // Read the source code count = (int) fread(*shader, 1, shadersize, fp); (*shader)[count] = '\0'; if (ferror(fp))

13 count = 0; fclose(fp); return 1; // public int installshaders(const GLchar *vertex, const GLchar *fragment) GLint vertcompiled, fragcompiled; // status values GLint linked; // Create a vertex shader object and a fragment shader object vertexshaderobject = glcreateshader(gl_vertex_shader); fragmentshaderobject = glcreateshader(gl_fragment_shader); // Load source code strings into shaders, compile and link glshadersource(vertexshaderobject, 1, &vertex, NULL); glshadersource(fragmentshaderobject, 1, &fragment, NULL); glcompileshader(vertexshaderobject); glgetshaderiv(vertexshaderobject, GL_COMPILE_STATUS, &vertcompiled); glcompileshader( fragmentshaderobject ); glgetshaderiv( fragmentshaderobject, GL_COMPILE_STATUS, &fragcompiled); if (!vertcompiled!fragcompiled) return 0; // Create a program object and attach the two compiled shaders programobject = glcreateprogram(); glattachshader( programobject, vertexshaderobject); glattachshader( programobject, fragmentshaderobject); // Link the program object gllinkprogram(programobject); glgetprogramiv(programobject, GL_LINK_STATUS, &linked); if (!linked) return 0; // Install program object as part of current state gluseprogram(programobject); // Set up initial uniform values gluniform3f(glgetuniformlocation(programobject, "LightPosition"), 2.0, 2.0, 4.0); gluniform1i(glgetuniformlocation(programobject, "texhandle"), 0); return 1; int init(void) const char *version;

14 GLchar *VertexShaderSource, *FragmentShaderSource; int loadstatus = 0; version = (const char *) glgetstring(gl_version); if (version[0] < '2' version[1]!= '.') printf("this program requires OpenGL >= 2.x, found %s\n", version); exit(1); gldepthfunc(gl_less); glenable(gl_depth_test); glclearcolor(1.0f, 1.0f, 1.0f, 1.0f); readshadersource("simpletex.vert", &VertexShaderSource ); readshadersource("simpletex.frag", &FragmentShaderSource ); loadstatus = installshaders(vertexshadersource, FragmentShaderSource); angleparam = glgetuniformlocation ( programobject, "angle" ); scalarparam = glgetuniformlocation ( programobject, "scalar" ); init2dtexture(); return loadstatus; void mytimer(int id) // timer callback cout << "Timer just went off" << endl; if (scalar == 1.0) scalar = 0.5; else scalar = 1.0; glutpostredisplay(); // request redraw gluttimerfunc(10000, mytimer, 0); // reset timer for 10 seconds static void Reshape(int w, int h) float vp = 0.8f; float aspect = (float) w / (float) h; glviewport(0, 0, w, h); glmatrixmode(gl_projection); glloadidentity(); glviewport(0, 0, w, h); glmatrixmode(gl_projection); glloadidentity(); // glortho(-1.0, 1.0, -1.0, 1.0, -10.0, 10.0); glfrustum(-vp, vp, -vp / aspect, vp / aspect, 3, 10.0); glmatrixmode(gl_modelview); glloadidentity(); gltranslatef(0.0, 0.0, -5.0); void CleanUp(void) gldeleteshader(vertexshaderobject); gldeleteshader(fragmentshaderobject); gldeleteprogram(programobject); glutdestroywindow(win); static void Idle(void)

15 gluniform1f( angleparam, angle ); angle += 0.01; gluniform1f( scalarparam, scalar ); glutpostredisplay(); static void Key(unsigned char key, int x, int y) switch(key) case 27: CleanUp(); exit(0); break; case 'x': anglex = ( anglex + 3 ) % 360; break; case 'X': anglex = ( anglex - 3 ) % 360; break; case 'y': angley = ( angley + 3 ) % 360; break; case 'Y': angley = ( angley - 3 ) % 360; break; case 'z': anglez = ( anglez + 3 ) % 360; break; case 'Z': anglez = ( anglez - 3 ) % 360; break; case 'r': anglex = angley = anglez = 0; break; case 't': objecttype = (objecttype + 1 ) % 3; break; glutpostredisplay(); void display(void) GLfloat vec[4]; glclear(gl_color_buffer_bit GL_DEPTH_BUFFER_BIT); glclearcolor( 1.0, 1.0, 1.0, 0.0 ); //get white background color glpushmatrix(); glrotatef( anglex, 1.0, 0.0, 0.0); glrotatef( angley, 0.0, 1.0, 0.0); glrotatef( anglez, 0.0, 0.0, 1.0); //rotate the cube along x-axis //rotate along y-axis //rotate along z-axis //glactivetexture(gl_texture0); glenable(gl_texture_2d); //glbindtexture(gl_texture_2d, texname); glbindtexture(gl_texture_2d, texname[0]); glbegin ( GL_POLYGON ); //back face gltexcoord2f (0,0); glvertex3f (0,0,0); gltexcoord2f (1,0); glvertex3f (1,0,0); gltexcoord2f (1,1);

16 glvertex3f (1,1,0); gltexcoord2f (0,1); glvertex3f (0,1,0); glend(); glbindtexture(gl_texture_2d, texname[1]); glbegin ( GL_POLYGON ); // front face gltexcoord2f (0,0); glvertex3f (0,0,1); gltexcoord2f (1,0); glvertex3f (1,0,1); gltexcoord2f (1,1); glvertex3f (1,1,1); gltexcoord2f (0,1); glvertex3f (0,1,1); glend(); glbindtexture(gl_texture_2d, texname[2]); glbegin ( GL_POLYGON ); // right face gltexcoord2f (0,0); glvertex3f (1,0,1); gltexcoord2f (1,0); glvertex3f (1,0,0); gltexcoord2f (1,1); glvertex3f (1,1,0); gltexcoord2f (0,1); glvertex3f (1,1,1); glend(); glbindtexture(gl_texture_2d, texname[3]); glbegin ( GL_POLYGON ); // left face gltexcoord2f (0,0); glvertex3f (0,0,1); gltexcoord2f (1,0); glvertex3f (0,0,0); gltexcoord2f (1,1); glvertex3f (0,1,0); gltexcoord2f (0,1); glvertex3f (0,1,1); glend(); glbindtexture(gl_texture_2d, texname[4]); glbegin ( GL_POLYGON ); // top face gltexcoord2f (0,0); glvertex3f (0,1,0); gltexcoord2f (1,0); glvertex3f (0,1,1); gltexcoord2f (1,1); glvertex3f (1,1,1); gltexcoord2f (0,1); glvertex3f (1,1,0); glend(); glbindtexture(gl_texture_2d, texname[5]); glbegin ( GL_POLYGON ); // bottom face gltexcoord2f (0,0); glvertex3f (0,0,0); gltexcoord2f (1,0); glvertex3f (0,0,1); gltexcoord2f (1,1); glvertex3f (1,0,1); gltexcoord2f (0,1); glvertex3f (1,0,0); glend(); glpopmatrix(); glutswapbuffers(); glflush(); gldisable(gl_texture_2d);

17 int main(int argc, char *argv[]) int success = 0; glutinit(&argc, argv); glutinitwindowposition( 0, 0); glutinitwindowsize(500, 500); glutinitdisplaymode(glut_rgb GLUT_DOUBLE GLUT_DEPTH); win = glutcreatewindow(argv[0]); glutreshapefunc(reshape); glutkeyboardfunc(key); glutdisplayfunc(display); gluttimerfunc(10000, mytimer, 0); glutidlefunc(idle); // Initialize the "OpenGL Extension Wrangler" library glewinit(); success = init(); if ( success ) glutmainloop(); return 0; //simpletex.vert uniform float angle; uniform float scalar; //value provided by application program //value provided by application program void main(void) gl_texcoord[0] = gl_multitexcoord0; float c = cos( angle ); float s = sin( angle ); mat4 ZRotationMatrix = mat4( c, -s, 0.0, 0.0, s, c, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0 ); mat4 YRotationMatrix = mat4( c, 0.0, s, 0.0, 0, 1, 0.0, 0.0, -s, 0.0, c, 0.0, 0.0, 0.0, 0.0, 1.0 ); mat4 XRotationMatrix = mat4( 1.0, 0.0, 0.0, 0.0, 0.0, c, -s, 0.0, 0.0, s, c, 0.0, 0.0, 0.0, 0.0, 1.0 ); mat4 ScalarMatrix = mat4( scalar, 0.0, 0.0, 0.0, 0.0, scalar, 0.0, 0.0, 0.0, 0.0, scalar, 0.0,

gl_modelviewprojectionmatrix * RotationMatrix * ScalarMatrix * gl_vertex; //simpletex.

18 0.0, 0.0, 0.0, 1.0 ); mat4 RotationMatrix = ZRotationMatrix * YRotationMatrix; gl_position = gl_modelviewprojectionmatrix * RotationMatrix * ScalarMatrix * gl_vertex; //simpletex.frag uniform sampler2d texhandle; void main (void) vec3 lightcolor = vec3 (texture2d(texhandle, gl_texcoord[0].st)); gl_fragcolor = vec4 (lightcolor, 1.0); And here are the source images used for the sides: back.png bottom.png

19 front.png left.png

20 right.png top.png Evaluation: I successfully completed all parts of the homework and am giving myself 40 points.

1)Write a shader program that renders a regular pentagon with textured image like the one shown below.

Andrew Yenalavitch CSE520 Winter 2015 Quiz 2 Report 1)Write a shader program that renders a regular pentagon with textured image like the one shown below. Use the following provided image for the texture: